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VLDB
1995
ACM
15 years 3 months ago
1995
ACM
In this paper we introduce generalized projections (GPs), an extension of duplicateeliminating projections, that capture aggregations, groupbys, duplicate-eliminating projections ...
VLDB
1995
ACM
15 years 3 months ago
1995
ACM
We provide several new sampling-based estimators of the number of distinct values of an attribute in a relation. We compare these new estimators to estimators from the database an...
VLDB
1995
ACM
15 years 3 months ago
1995
ACM
Traditionally, optimizers are “programmed” to optimize queries following a set of buildin procedures. However, optimizers should be robust to its changing environment to gener...
111
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SIGMOD
2008
ACM
14 years 11 months ago
2008
ACM
James Nicholas Gray's understanding and experimentation gave him a special perspective. From 1995 his commitment was building indefinitely scalable tools by working on really...
109
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ACM
1995
15 years 3 months ago
1995
We study properties of rough sets, that is, approximations to sets of records in a database or, more formally, to subsets of the universe of an information system. A rough set is a...